1. Technical Field
The present disclosure relates to a printing apparatus and a printing method.
2. Related Art
In the related art, printing apparatuses that form (print) images on a target print medium using a liquid material by discharging liquid droplets of the liquid material from a discharge head and landing the liquid droplets onto arbitrary positions of the target print medium, have been known.
The discharge head discharges liquid droplets at loci (timings) that correspond to positions which are to be landed onto while being moved relatively with respect to the target print medium. The liquid droplets that are discharged from the discharge head fly to the target print medium and land onto landing positions on the target print medium. The flight time of the liquid droplets is a time that is obtained by dividing a distance (hereinafter referred to as “head gap”) between discharge holes in a discharge direction of the liquid droplets from the discharge holes in the discharge head and landing positions on the target print medium by the flight speed of the liquid droplets. A distance in a relative movement direction of the discharge head and the target print medium between the discharge holes and the landing positions is the product of the relative movement speed and the flight time. Therefore, in order to maintain the positional accuracy of landing positions at a high level, it is necessary to maintain the relative movement speed and the flight time as constants.
However, there are cases in which the target print medium is deformed such as when warping occurs due to dead loads or heating in treatment processes prior to printing. In a case in which the target print medium has been deformed, since the head gap is no longer constant, the flight time of the liquid droplets is no longer constant. As a result of this, there are cases in which the accuracy of the landing positions is impaired.
An ink jet-type printing recording apparatus that is provided with a distance measurement section that measures the distance between a print head and a target print body and a control section that changes an ejection speed of ink droplets from the print head depending on the measured distance, is disclosed in JP-A-9-29958. According to JP-A-9-29958, using the ink jet-type printing recording apparatus, it is even possible to perform printing with high accuracy without printed characters becoming distorted in a case in which there is a change in the distance between the print head and the target print body.
However, since it is not possible to reduce a discharge period of the print head to be shorter than a measurement period of the distance measurement section in order to measure the distance (head gap) between the print head and the target print body for each landing point, there is a problem in that the printing speed is limited. It is also possible to reduce the number of positions at which the head gap is measured in order to maintain the printing speed, but in such a case, there are problems in that the land accuracy is impaired at positions where the head gap is not measured, and there is a high probability that printed image quality would be impaired as a result of shifting of the landing positions.